Biosynthesis, protease optimization and purification of alkaline serine from Shewanella algae and its potential application as silver recovery

Abstract

The current study proposes an substitute method to recover silver from trash X-ray film as opposed to conventional methods that are costly and hazardous to the environment. The isolated bacterium was taxonomically identified as Shewanella algae through 16S rRNA gene sequence analysis. The significant factors for protease production (Gelatin, Beef extract, pH and Temperature) were optimized by Box-Benhen factorial design. The predicted and actual values of protease activity were recorded as 162% and 152%, respectively, through RSM. The purified 45 KDa bacterial enzyme unveiled stability in a extensive range of pH (7.0–10.0) and temperature (40-60 °C) with protease activity at pH 9.0 and 50 °C. The purified proteolytic enzyme withstand in the existence of solvents, surfactants and metal ions. Further, the purified protease was inhibitor of (PMSF) can inhibit the Shewanella algae alkaline protease. In this study, protease of 150 U/ml and could effectively hydrolyze the gelatin layer within 60 min.